This invention relates to an apparatus and method for securing curtain wall system supports to a building, specifically an improvement to a mullion connection system and erection process while allowing three-directional and rotational adjustability to absorb building erection tolerances.
A typical curtain wall system on a building comprises multiple spaced-apart mullion assemblies connected to a building frame or floor slab edges to support multiple curtain wall facing panels that are connected to the mullion assemblies. The primary functions of the assembled mullions and a mullion-supported curtain wall are to provide interior and exterior aesthetic appearance of the building envelope and to provide a weather shield against wind, rain and temperature variations.
It is well known that the aesthetic appearance of a building is related to horizontal and vertical alignments as well as surface contours of the curtain wall panels. It is also well known that significant erection tolerances exist in building frame and floor slab construction that are typically used to support a curtain wall assembly. Therefore, the aesthetic appearance of the curtain wall system typically relies at least in part on the adjustability in field connections and positioning the mullions supporting the curtain wall and an mullion erection process which may include rotational adjustment and three-directional adjustments, i.e. up-and-down; in-and-out; left-and-right position adjustments. Some or all of these adjustments are typically designed into a mullion connection system and process which may include temporary mullion positioning tools and supports, a floor anchoring assembly, an up/down adjusting component, an in/out as well as rotational adjusting component, a left/right adjusting component, and structural connections between the components and the floor anchoring assembly. Due to the multiple structural connections involving multiple position changes, the desired position and connection strength can be compromised by faulty field executions and temporary supports required during the erection process.
One or more of the principal objectives of the present invention include the following:
(1) to reduce the number of primary mullion connection components to preferably two, a pair of mullion connection clips attachable to a building anchor and a mullion section;
(2) to simplify the position adjustments of the mullion being supported;
(3) to reduce the number of fasteners required to be secured in the field; and
(4) to simplify the field hoisting of mullions during erection.
One or more of these and/or other objectives of the present invention are accomplished by preferably providing a self supporting and multi-adjustable mullion connector allowing at least four degrees of positional freedom for connecting a curtain wall support or mullion to a building structure. The preferred mullion connector comprises a first leg and a second leg in a plane generally perpendicular to the first leg, the first leg having a first fastener opening which, in combination with a non-circular mullion fastener opening, absorbs floor slab level tolerance variations. A second leg having a second non-circular fastener opening is capable of absorbing in/out and left/right erection tolerances. By placing the second leg on a generally horizontal surface such as a building floor, and loosely fastening the second leg through the second fastener opening to a building anchor, the first leg opening may be attached to the mullion allowing rotation and up and down adjustment and when combined with the second leg fastener opening allows rotational, in and out, and left to right adjustment while supporting the mullion. In addition, the assembled mullion connector and mullion section in a first configuration may also be used to hoist the mullion section and mullion connector to its assembly position on the face of the building prior to changing the configuration and connecting the assembly to the building.